394 • DR R. W, SHUFteLDT. 



bone is carried forwards and inwards as a process. Sjjheniscus 

 minor and mendicidus also have the foramen, and its anterior 

 margin may exhibit a slight apophysial protrusion. 



Pengviins have large orbital cavities, and this is particularly 

 the case in Ajjtenodytes, where, however, the walls are not 

 especially complete, except below, the floor being formed by the 

 very wide palatine and greatly flattened out pterygoid upon 

 either side. Owing in part to this unusual size of the orbit in 

 A. pemiantii the zygoma is decidedly arched in order to accom- 

 modate itself to the circularity of the cavity; from quadrate 

 to lacrymal bone, the bar makes a low, curving sweep, the con- 

 cavity, of course, being upon its upper side. This curve of 

 the zygoma is likewise enjoyed in a similar degree by the ramus 

 of the mandible, while this condition is scarcely at all notice- 

 able, either in the case of the zygoma or mandible, in Spheniscus 

 demersus, nor in other species of the same genus. 



The quadrate hone is well developed in all Penguins, it having- 

 a double mastoidal head with a distinct antero-posterior groove 

 dividing the facets ; a triangular laterally-compressed orbital 

 process (smallest in Eiulyptes) ; a deep, capacious, and anteriorly 

 notched cup for the quadrato-jugal ; and a large, transversely 

 placed facet for the mandibular articulation. This last is also 

 separated into two facets byja middle groove, and the free end 

 of the orbital process is truncated, and finished off with a bony 

 nib. Many interesting characters are to be found upon the 

 basal aspect of the skull fin any species of the Spheniscidm. 

 The subcircular foramen magnum is remarkably large, and the 

 condyle, likewise of pretty good proportions, is sessile. In 

 front of this the basi-temporal area is smooth and flat, it being 

 surrounded by a raised margin in front, and by the conspicuous, 

 paroccipitals at the sides. These anterior bony boundaries are 

 best marked in Sjyheniscus and Eudyptes. Either j^i^^'VlM^ ^^ 

 much spread out ; flattened completely from above downwards^ 

 and more or less triangular in form, — an isosceles triangle in 

 fact, with its base to the front (when in situ), and with the 

 inner basal angle articulating with the hinder end of the 

 palatine of the same side and with the sphenoidal rostrum. In 

 Ajjienodytes pennantii, the pterygoid is less evidently triangular; 

 its base is largely in contact with the border of the palatine 



